Drugs used to treat cardiovascular or pulmonary diseases, or diabetes are the most frequent causes of hospitalizations and emergency department visits due to suboptimal therapy or adverse drug events (ADEs). The lack of communication and coordination between the inpatient setting and the community setting contributes to these problems. ADEs occur in 25% of ambulatory patients and may cause 17% of hospital admissions among the elderly. Expanded roles for pharmacists have been suggested to reduce ADEs. Previous studies that examined information transfer between inpatient and community pharmacists had small sample sizes, did not include the primary care physician, nor did they evaluate the effect of the communication on ADEs, hospitalizations or unscheduled visits. These information gaps in the research need to be addressed in order to identify optimal strategies to improve therapy and reduce ADEs. The primary objective of this application is to test whether providing a pharmacy case manager to: 1) reconcile medications on admission and discharge, 2) increase patient understanding, and 3) provide post-discharge follow-up of medication use, and 4) increasing communication of discharge medication plans to community physicians and pharmacists will reduce ADEs in patients with selected cardiovascular or pulmonary diseases or diabetes. This will be a randomized, prospective study to evaluate the impact of enhanced continuity of pharmacy care on appropriateness of therapy, ADEs, hospitalizations or unscheduled visits. Patients (n = 1000) admitted to the university hospital will be randomized to a control, minimal intervention or enhanced intervention group. For the enhanced intervention group, a hospital pharmacist case manager will provide: 1) an admission medication history, 2) a discharge summary and patient education, 3) transfer of discharge summary data to the community physician and pharmacist, 4) telephone follow-up 3-5 days post-discharge, and 5) communication and recommendations to the physician and pharmacist in the community. The minimal intervention group will receive: 1) the admission medication history, and 2) a discharge summary and education. The study will be one of the most comprehensive characterizations of ADEs and their prevention ever conducted. There is a high probability that this intervention can impact patient care by reducing the burden of ADEs in older patients who are at high risk for medication-related problems.